A stacking-type header is known in the art that distributes and supplies refrigerant to heat transfer tubes of a heat exchanger. This stacking-type header includes a plurality of plates stacked on one another to form distribution passages extending from one inlet passage to a plurality of outlet passages. Such a configuration allows the refrigerant to be distributed and supplied to the heat transfer tubes, serving as the distribution passages, of the heat exchanger (see Patent Literature 1, for example).